The long-term goal of this proposal is to advance our knowledge by employing imaging techniques using a small animal positron emission tomograph (microPET Focus 120). This instrument has high resolution and high sensitivity and will therefore allow the study of biochemical mechanisms with greater detail in small animals than has been possible before. The Brain Imaging Center (BIC), Center for Functional Onco-Imaging (CFOI), Departments of Pharmacology, Anatomy and Neurobiology, Neurobiology and Behavior, Biological Chemistry, Medicine, Transdisciplinary Tobacco Use Research Center (TTURC), Radiopharmaceutical Laboratories all at University of California-Irvine (UCI) have been involved in using imaging methodology to study normal and abnormal physiological processess. Researchers at UCI have a long tradition of using PET in human studies of various conditions. A large number of researchers at the various centers and Departments in UCI are involved in studying rodent models. The acquisition of a microPET scanner will allow researchers in numerous projects to study in vivo brain function with a resolution of about 1.5 mm or less. For the first time, investigators at UCI will be able to accurately assess functional activity in small regions in the brain noninvasively. Imaging research at UCI is unique in terms of the close association of investigators in basic animal research with clinical research as exemplified in the various programs. Studies carried out on the animal models will greatly enhance our ability to understand and interpret human studies. The new microPET scanner will be housed in Irvine Hall, where the BIC and Center for CFOI are located and houses the human PET scanners, the MC-17 medical cyclotron, radiopharmaceutical laboratories, MR scanners, Optical Imaging Lab and rodent animal facility. The microPET scanner will be under the direction of Dr. Jogesh Mukherjee, and a team from five different departments (Radiology, Medicine, Pharmacology, Neurobiology and Behavior and Biological Chemistry) that will provide administrative, scientific, and technical expertise necessary for the effective operation and maximal utilization of the microPET will be in place.